X-Message-Number: 13442 Date: Thu, 30 Mar 2000 21:33:59 -0800 (PST) From: Doug Skrecky <> Subject: peg might be a useful addition to vitrification solutions (note: peg 200 can penetrate tissue) Citations: 1-2 <1> Authors Sutton RL. Institution MRC Medical Cryobiology Group, University Department of Surgery, Cambridge, United Kingdom. Title Critical cooling rates for aqueous cryoprotectants in the presence of sugars and polysaccharides. Source Cryobiology. 29(5):585-98, 1992 Oct. Abstract The technique of isothermal emulsion differential scanning calorimetry was used to determine time-temperature-transformation (TTT) curves for aqueous glycerol and butane-2,3-diol in the presence of various polysaccharides and sugars. The critical cooling rate required to avoid the crystallization of ice in these solutions was then calculated from the experimental TTT curves. The polysaccharides used in this study included starch hydrolysis products and dextrans of various molecular weights. The sugars used here were sucrose, glucose, trehalose, and raffinose. The results show that the critical cooling rates of butane-2,3-diol and glycerol are reduced by varying amounts by the addition of such materials but that the reduction is not as great as is achieved by the addition of polyethylene glycol with a molecular weight of 400. <2> Authors Banker MC. Layne JR Jr. Hicks GL Jr. Wang T. Institution Department of Surgery, University of Rochester, N.Y. 14642. Title Freezing preservation of the mammalian heart explant. III. Tissue dehydration and cryoprotection by polyethylene glycol. Source Journal of Heart & Lung Transplantation. 11(4 Pt 1):619-23, 1992 Jul-Aug. Abstract Isolated rat hearts perfused with hyperosmotic Krebs-Henseleit buffer containing 60 mmol/L NaCl lose 10% of their tissue water. Perfusion of the rat hearts with Krebs-Henseleit buffer containing polyethylene glycol 8000 caused a concentration-dependent reduction in tissue water. In a study of the effect of different cryoprotectants on cardiac preservation, isolated rat hearts were flushed with a cardioplegic solution (CP-14), or CP-14 with either 50 mmol/L glycerol (CP-15), or 5% polyethylene glycol (CP-16) and frozen at -1.4 degrees C for 5 hours. Thawed hearts were reperfused in working mode to assess function. There was no recovery in CP-14 hearts. Hearts treated with CP-15 recovered 39.3% +/- 2.9% (mean +/- SEM) of control cardiac output. CP-16 boosted the recovery of cardiac output to 54.4% +/- 5.7% (p less than 0.05 vs CP-15). Glycerol significantly reduced tissue ice content; PEG further decreased the ice content to 31.7% +/- 0.6%, which was distinctively lower than that in CP-14 (44.7% +/- 1.1%) and in CP-15 hearts (34.6% +/- 1.1%). Tissue water content of CP-14 and CP-15 hearts was similar (3.83 and 3.87 gm H2O/gm dry weight). Polyethylene glycol reduced the tissue water content to 3.24 +/- 0.04 gm H2O/gm dry (p less than 0.01 vs CP-14 and CP-15 by ANOVA). Thus both glycerol and polyethylene glycol offered cryoprotection to the heart explant by reducing tissue ice formation. Polyethylene glycol was superior to glycerol by dehydrating myocardial tissue and further minimizing freezing damage. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=13442